//定义懒加载插件
import { useIntersectionObserver } from '@vueuse/core'

export const lazyPlugin = {
    install (app){
        //懒加载指令逻辑
        //定义全局指令
app.directive('img-lazy',{
    mounted (el,binding) {
    //el：指令绑定的那个元素 img
    //binding：binding.value 指令等于号后面绑定的表达式的值
         const {stop} = useIntersectionObserver(
            el,
            ([{ isIntersecting }]) => {
                console.log(isIntersecting);
                if (isIntersecting){
                    //进入视口区域
                    el.src = binding.value
                    stop()
                }
            },
          )
    }
})
    }
}